The present invention relates to a manufacturing method of high concentration ozone gas and an apparatus thereof using a pressure swing adsorption apparatus (PSA apparatus) having plural adsorbing layers filled with a specific high silica ozone adsorbent large in the difference of ozone adsorbing amount between adsorption pressure and desorption pressure, that is, the ozone adsorbing capability.
The invention also relates to a manufacturing method of high concentration ozone gas and an apparatus thereof for concentrating ozone by a temperature swing adsorption system for changing over an ozone adsorbing process at a relatively low temperature and an ozone recovery process at a relatively high temperature, by using a specific ozone adsorbent having a high ozone adsorbing capability even in the presence of water.
Ozone is produced by using silent discharge apparatus or water electrolytic apparatus, but the ozone gas obtained from these apparatuses are low in concentration, and it is usually used after concentrating by an ozone adsorbing apparatus or the like.
As an ozone concentrating apparatus, an oxygen recycling ozone generating apparatus using liquid oxygen is proposed (Japanese Patent Application Laid-open No. 53-64690). A schematic diagram of this apparatus is shown in FIG. 15. It is a feature of this apparatus that liquid oxygen is used as the oxygen material. This liquid oxygen 31 is fed into an ozone generating apparatus 32, and the gas containing the ozone is cooled to about xe2x88x9260xc2x0 C. by a heat exchanger 33 and a refrigerating machine 34, it is further fed into an ozone adsorbing tower 35 filled with silica gel to adsorb ozone, the gas containing oxygen flowing out from the adsorbing tower 35 is fed into the heat exchanger 33 to cool the gas containing the ozone, and it is returned to the material side of the ozone generating apparatus 32. On the other hand, the adsorbing tower 35 having adsorbed the ozone is transferred to the desorbing process, and the air 37 dried by a dryer 36 is heated by a heat exchanger 38, and is fed into the ozone adsorbing tower 35 to be heated, purged and desorbed, and a concentrated ozone gas 37 is recovered, while the desorbed concentrated ozone gas 39 is fed into the heat exchanger 38, and the dried air is heated. Consequently, the regenerated adsorbing tower 35 by desorbing the ozone is transferred from the desorbing process to the adsorbing process.
Thus, the silica gel is known as ozone adsorbent, but since it is extremely large in the moisture adsorbing capability as compared with ozone, if moisture is present in the gas contacting with the adsorbent (the gas to be treated, purge gas, and the like), the moisture is preferentially adsorbed by the silica gel, and it is hard to desorb the once adsorbed moisture, and the moisture is accumulated, and hence it is difficult to maintain a specific ozone adsorbing capability. As a result, an extremely large amount of silica gel is needed for maintaining a specific gas treating capacity, and the adsorbing apparatus itself is increased in its size. Besides, when adsorption and desorption of moisture are repeated, the silica gel is powdered and may be lowered in the adsorbing capability.
In the aforesaid apparatus, using liquid oxygen as oxygen material, by preliminarily drying the purge gas and feeding into the adsorbing tower, moisture is prevented from mixing into the adsorbing tower filled with silica gel, and the ozone adsorbing amount is increased by utilizing the low temperature of the liquid oxygen.
Generally, the ozone adsorbing amount is larger as the temperature is lower, but it is hard to cool lower than xe2x88x9260xc2x0 C. unless a particular refrigerating machine is used, and a large amount of adsorbent is usually required for increasing the treated gas amount, and the apparatus becomes larger in size, which causes to increase the manufacturing cost and running cost of the apparatus.
It is hence an object of the invention to solve the above problems, and provide a method and apparatus for manufacturing high concentration ozone gas capable of concentrating ozone efficiently, by using a specific high silica ozone adsorbent excellent in ozone adsorbing capability even in the presence of moisture, and applying this adsorbent in a pressure swing adsorbing apparatus or a temperature swing adsorbing apparatus. Moreover, by combining a specific ozone generating apparatus and the pressure swing adsorbing apparatus or temperature swing adsorbing apparatus, it is also intended to provide a method and apparatus for manufacturing high concentration ozone further excellent in the ozone concentrating efficiency.
Invention of First Group
The invention of a first group succeeded in solving the above problems by employing the following constitution.
(1) A manufacturing method of high concentration ozone gas, characterized by employing a pressure swing adsorbing apparatus having a plurality of adsorbing layers filled with ozone adsorbent, adsorbing ozone by feeding gas containing ozone at a relatively high pressure into the adsorbing layers in the adsorbing process, and recovering concentrated ozone gas by setting the adsorbing layers of the desorbing process to a relatively low pressure, in which the ozone adsorbent is an adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate.
(2) A manufacturing method of high concentration ozone gas according to (1), in which the high silica pentasyl zeolite has the SiO2/Al2O3 ratio of 70 or more, preferably 100 or more, dealuminized fogersite has the SiO2/Al2O3 ratio of 20 or more, preferably 50 or more, and mesoporous silicate has the SiO2/Al2O3 ratio of 20 or more, preferably 50 or more.
(3) A manufacturing method of high concentration ozone gas according to (1) or (2), in which the adsorbing layers in the adsorbing process are held at temperature of xe2x88x9260xc2x0 C. to 25xc2x0 C.
(4) A manufacturing method of high concentration ozone gas according to any one of (1) to (3), in which the adsorbing pressure in the adsorbing process is selected in a range of 1.05 to 5 atm, and the desorbing pressure of the desorbing process is selected in a range of 0.04 to 0.3 atm.
(5) A manufacturing method of high concentration ozone gas according to any one of (1) to (4), in which the changeover time of the pressure swing adsorbing apparatus is selected in a range of 1 to 10 minutes.
(6) A manufacturing method of high concentration ozone gas according to any one of (1) to (5), in which part of the high pressure oxygen concentrated gas flowing out from the adsorbing layers in the adsorbing process is decompressed by a reducing valve, and is fed into the adsorbing layers in the desorbing process to be purged.
(7) A manufacturing method of high concentration ozone gas according to (6), in which the purge rate in the purge operation is selected in a range of 1 to 2.
(8) A manufacturing method of high concentration ozone gas according to any one of (1) to (7), in which ozone is generated by using a water electrolytic ozone generating apparatus of high pressure, the gas containing ozone is fed into the adsorbing layers in the adsorbing process of the pressure swing adsorbing apparatus, and part of the high pressure oxygen concentrated gas flowing out from the adsorbing layers in the adsorbing process is returned to the hydrogen electrode chamber of the water electrolytic ozone generating apparatus to depolarize the oxygen.
(9) A manufacturing method of high concentration ozone gas according to any one of (1) to (7), in which ozone is generated by using a silent discharge ozone generating apparatus of high pressure specification, the gas containing ozone is fed into the adsorbing layers in the adsorbing process of the pressure swing adsorbing apparatus, and part of the high pressure oxygen concentrated gas flowing out from the adsorbing layers in the adsorbing process is returned to the material side of the silent discharge ozone generating apparatus.
(10) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a pressure swing adsorbing apparatus having plural adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a water electrolytic ozone generating apparatus of high pressure, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a compressor and a changeover valve are attached to a lead pipe for feeding gas containing ozone for connecting the ozone generating apparatus to the adsorbing layers in an adsorbing process, a lead pipe for circulating oxygen concentrated gas flowing out from the adsorbing layers is connected to a hydrogen electrode chamber of the water electrolytic ozone generating apparatus through the changeover valve so as to depolarize the oxygen, a lead pipe for feeding purge gas branched off the lead pipe for circulating oxygen concentrated gas is connected to the adsorbing layers in a desorbing process through a reducing valve and changeover valve, and a control device is provided for changing over all the changeover valves to set the adsorbing layers alternately in the adsorbing process and desorbing process by connecting a lead pipe for recovering ozone to the adsorbing layers in the desorbing process through a changeover valve to recover high concentration ozone gas.
(11) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a pressure swing adsorbing apparatus having plural adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a silent discharge ozone generating apparatus of high pressure, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a compressor and a changeover valve are attached to a lead pipe for feeding gas containing ozone for connecting the ozone generating apparatus to the adsorbing layers in an adsorbing process, a lead pipe for circulating oxygen concentrated gas at a relatively high pressure flowing out from the adsorbing layers is connected to a lead pipe for feeding oxygen material of the silent discharge ozone generating apparatus, a lead pipe for feeding purge gas branched off the lead pipe for circulating oxygen concentrated gas is connected to the adsorbing layers in a desorbing process through a reducing valve and changeover valve, and a control device is provided for changing over all the changeover valves to set the adsorbing layers alternately in the adsorbing process and desorbing process by connecting a lead pipe for recovering ozone to the adsorbing layers in the desorbing process through a changeover valve to recover high concentration ozone gas.
In this constitution, the invention of the first group can efficiently concentrate the ozone even in the presence of moisture, and thereby the manufacturing apparatus of high concentration ozone gas is reduced in size, and the manufacturing cost and running cost of the apparatus are substantially reduced. Moreover, when combined with the silent discharge ozone generating apparatus of high pressure or water electrolytic ozone generating apparatus of high pressure, matching with the pressure swing adsorbing apparatus is enhanced, and moreover by feeding the concentrated oxygen gas in the adsorbing process into the hydrogen electrode of the water electrolytic ozone generating apparatus, the oxygen depolarizing action is promoted, and the power to be applied can be decreased.
Invention of Second Group
The invention of a second group succeeded in solving the above problems by employing the following constitution.
(12) A manufacturing method of high concentration ozone gas, using two or more adsorbing layers filled with ozone adsorbent, employing a temperature swing adsorbing system for transferring the adsorbing layers from an adsorbing process at a relatively low temperature to a desorbing process at a relatively high temperature, and further returning to the adsorbing process, precooling the gas containing ozone from an ozone generating apparatus and feeding into the adsorbing layers in the adsorbing process, discharging oxygen concentrated gas at a relatively low temperature from the adsorbing layers, passing purge gas at a relatively high temperature into the adsorbing layers in the desorbing process in an opposite direction of the gas flow in the adsorbing process, and recovering the concentrated ozone gas continuously, in which the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, and the gas containing ozone from the ozone generating apparatus is cooled by the oxygen concentrated gas at a relatively low temperature flowing out from the adsorbing layers in the adsorbing process.
(13) A manufacturing method of high concentration ozone gas according to (12), in which the high silica pentasyl zeolite has the SiO2/Al2O3 ratio of 70 or more, dealuminized fogersite has the SiO2/Al2O3 ratio of 20 or more, and mesoporous silicate has the SiO2/Al2O3 ratio of 20 or more.
(14) A manufacturing method of high concentration ozone gas according to (12) or (13), using three or more adsorbing layers and employing a temperature swing adsorbing system for transferring the adsorbing layers from an adsorbing process at a relatively low temperature to a desorbing process at a relatively high temperature, and further returning to the adsorbing process through a cooling process, in which part of oxygen concentrated gas at a relatively low temperature flowing out from the adsorbing process is fed into the adsorbing layers in the cooling process and is cooled.
(15) A manufacturing method of high concentration ozone gas according to any one of (12) to (14), in which part of oxygen concentrated gas at a relatively low temperature flowing out from the adsorbing process is heated to purge temperature, and is passed into the adsorbing layers in the desorbing process in an opposite direction of the gas flow in the adsorbing process, and the ozone is heated, purged and desorbed.
(16) A manufacturing method of high concentration ozone gas according to any one of (12) to (15), in which purge gas suited to the purpose of use of the high concentration ozone gas is heated to purge temperature, and is passed into the adsorbing layers in the desorbing process in an opposite direction of the gas flow in the adsorbing process, and the ozone is heated, purged and desorbed.
(17) A manufacturing method of high concentration ozone gas according to any one of (12) to (16), in which the purge rate in the purge operation is selected in a range of 1 to 2.
(18) A manufacturing method of high concentration ozone gas according to any one of (12) to (17), in which the adsorbing temperature of the adsorbing process is selected in a range of xe2x88x92100xc2x0 C. to xe2x88x9230xc2x0 C., preferably in a range of xe2x88x9260xc2x0 C. to xe2x88x9230xc2x0 C., and the desorbing temperature of the desorbing process is selected in a range of 0xc2x0 C. to 50xc2x0 C.
(19) A manufacturing method of high concentration ozone gas according to any one of (12) to (18), in which the adsorbing pressure of the adsorbing process is selected in a range of 1 to 4 atm.
(20) A manufacturing method of high concentration ozone gas according to any one of (12) to (19), in which the changeover time of the temperature swing adsorbing system is selected in a range of 10 to 60 minutes.
(21) A manufacturing method of high concentration ozone gas according to any one of (12) to (20), using a water electrolytic ozone generating apparatus as the ozone generating apparatus, in which part of the oxygen concentrated gas flowing out from the adsorbing layers in the adsorbing process is returned to the hydrogen electrode chamber of the water electrolytic ozone generating apparatus to depolarize the oxygen.
(22) A manufacturing method of high concentration ozone gas according to anyone of (12) to (20), using a silent discharge ozone generating apparatus as the ozone generating apparatus, in which part of the oxygen concentrated gas flowing out from the adsorbing layers in the adsorbing process is returned to the oxygen material side of the silent discharge ozone generating apparatus.
(23) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a temperature swing adsorbing apparatus having plural adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a water electrolytic ozone generating apparatus, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a heat exchanger, a cooler and a changeover valve are attached to a lead pipe for feeding gas containing ozone for connecting the ozone generating apparatus to the adsorbing layers in an adsorbing process, a lead pipe for circulating oxygen concentrated gas at a relatively low temperature flowing out from the adsorbing layers is connected to the heat exchanger through the changeover valve, the gas containing ozone is precooled by the oxygen concentrated gas at relatively low temperature in the heat exchanger, the outlet side of the oxygen concentrated gas at a relatively low temperature of the heat exchanger is connected to a hydrogen electrode chamber of the water electrolytic ozone generating apparatus through a lead pipe, the oxygen concentrated gas at a relatively low temperature is supplied into the hydrogen electrode chamber to encourage the oxygen depolarization action, a lead pipe for feeding purge gas is branched off from the lead pipe for circulating the oxygen concentrated gas at a relatively low temperature, and is connected to the adsorbing layers in a desorbing process, a heater and a changeover valve are attached to the lead pipe for feeding purge gas to supply the oxygen concentrated gas at a relatively low temperature to the adsorbing layers as heating purge gas, the other end of the adsorbing layers in the desorbing process is connected to a lead pipe for recovering high concentration ozone gas through the changeover valve, and all the changeover vales are changed over simultaneously to use the adsorbing layers alternately in the adsorbing process and desorbing process.
(24) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a merry-go-round type temperature swing adsorbing apparatus having three or more adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a water electrolytic ozone generating apparatus, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a lead pipe for feeding gas containing ozone from the ozone generating apparatus and a lead pipe for circulating oxygen concentrated gas can be connected before and after the adsorbing layers in an adsorbing process, a lead pipe for feeding heating purge gas and a lead pipe for recovering high concentration ozone gas can be connected before and after the adsorbing layers in a desorbing process, a lead pipe for feeding cooling gas branched off from the lead pipe for circulating the oxygen concentrated gas and a lead pipe for recovery of the cooling gas can be connected before and after the adsorbing layers in a cooling process, the adsorbing process, desorbing process and cooling process are transferred sequentially by rotating the merry-go-round composed of the adsorbing layers, a heat exchanger and a cooler are attached to the lead pipe for feeding gas containing oxygen, the lead pipe for circulating oxygen concentrated gas is connected to the heat exchanger, the gas containing ozone is precooled by the oxygen concentrated gas at relatively low temperature flowing out from the adsorbing layers in the adsorbing process, the outlet side of the oxygen concentrated gas at a relatively low temperature of the heat exchanger is connected to a hydrogen electrode chamber of the water electrolytic ozone generating apparatus through a lead pipe, and the oxygen concentrated gas at a relatively low temperature is supplied into the hydrogen electrode chamber to encourage the oxygen depolarization action.
(25) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a temperature swing adsorbing apparatus having plural adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a silent discharge ozone generating apparatus, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a heat exchanger, a cooler and a changeover valve are attached to a lead pipe for feeding gas containing oxygen for connecting the ozone generating apparatus to the adsorbing layers in an adsorbing process, a lead pipe for circulating oxygen concentrated gas at a relatively low temperature flowing out from the adsorbing layers is connected to the heat exchanger through a changeover valve, the gas containing ozone is precooled by the oxygen concentrated gas at a relatively low temperature in the heat exchanger, the outlet side of the oxygen concentrated gas at a relatively low temperature of the heat exchanger is connected to the oxygen material supply side of the silent discharge ozone generating apparatus through a lead pipe so as to recycle the oxygen concentrated gas, a lead pipe for feeding purge gas is branched off from the lead pipe for circulating oxygen concentrated gas at a relatively low temperature and is connected to the adsorbing layers in a desorbing process, a heater and a changeover valve are attached to the lead pipe for feeding purge gas so that the oxygen concentrated gas at a relatively low temperature may be supplied to the adsorbing layers as heating purge gas, other end of the adsorbing layers in the desorbing process is connected to a lead pipe for recovering high concentration ozone gas through the changeover valve, and all the changeover valves are changed over simultaneously to use the adsorbing layers alternately in the adsorbing process and desorbing process.
(26) A manufacturing apparatus of high concentration ozone gas, comprising an ozone generating apparatus, and a merry-go-round type temperature swing adsorbing apparatus having three or more adsorbing layers filled with ozone adsorbent, in which the ozone generating apparatus is a silent discharge ozone generating apparatus, the ozone adsorbent is one or two or more kinds of adsorbent selected from the group consisting of high silica pentasyl zeolite, dealuminized fogersite, and mesoporous silicate, a lead pipe for feeding gas containing ozone from the ozone generating apparatus and a lead pipe for circulating oxygen concentrated gas can be connected before and after the adsorbing layers in an adsorbing process, a lead pipe for feeding heating purge gas and a lead pipe for recovering high concentration ozone gas can be connected before and after the adsorbing layers in a desorbing process, a lead pipe for feeding cooling gas branched off from the lead pipe for circulating the oxygen concentrated gas and a lead pipe for recovery of the cooling gas can be connected before and after the adsorbing layers in a cooling process, the adsorbing process, desorbing process and cooling process are transferred sequentially by rotating the merry-go-round composed of the adsorbing layers, a heat exchanger and a cooler are attached to the lead pipe for feeding gas containing oxygen, the lead pipe for circulating oxygen concentrated gas is connected to the heat exchanger, the gas containing ozone is precooled by the oxygen concentrated gas at relatively low temperature flowing out from the adsorbing layers in the adsorbing process, and is further cooled to the adsorbing temperature by the cooler, and the outlet side of the oxygen concentrated gas at a relatively low temperature of the heat exchanger is connected to oxygen material supply side of the silent discharge ozone generating apparatus through a lead pipe so that the oxygen concentrated has can be recycled.
In this constitution, the invention of the second group can efficiently concentrate the oxygen even in the presence of moisture, and thereby the manufacturing apparatus of high concentration ozone gas is reduced in size, and the manufacturing cost and running cost of the apparatus are substantially reduced. Moreover, by feeding the concentrated oxygen gas flowing out from the adsorbing process into the hydrogen electrode of the water electrolytic ozone generating apparatus, the oxygen depolarizing action is promoted, and the power to be applied can be decreased. Besides, by returning the concentrated oxygen gas flowing out from the adsorbing process to the oxygen material side of the silent discharge ozone generating apparatus, the concentrated oxygen can be utilized effectively.